Speak to enough people in the art world, and you get the impression that if James Palmer were a still-life painting, he’d be a lightning rod.

The founder of Mondex Corp., a 23-year-old Toronto-based company, he is controversial for his approach to pursuing the recovery of Nazi-looted artworks to return to the heirs of their original owners. But rather than being lauded for his Robin Hood efforts, Palmer is characterized by multiple sources who spoke to The Post as an “art-world ambulance chaser.”

Some in the art-recovery business criticize Palmer for going about things backward: finding the art and then soliciting the potential heir, as opposed to being approached by a person and finding their art.

His typical process works like this: scour auctions and looted-art databases for potentially stolen work; use high-tech genealogy to figure out who an heir might be; press said heir to contract with Mondex; then launch a legal battle to regain the work or settle with the current owner for restitution. Palmer keeps up to 39 percent of the art’s value if he wins.

Mondex is behind a suit against New Yorkers David and Helly Nahmad, father-son art-dealing billionaires. They’re accused of possessing a 1918 Modigliani painting, “Seated Man With a Cane,” that had allegedly been looted by Nazis from dealer Oscar Stettiner.

The recent Panama Papers revealed the Nahmads’ possession of the work, which they purchased at a Christie’s auction in 1996, for $3.2 million. Stettiner’s grandson Philippe Maestracci, with the backing of Mondex, is litigating for the work’s return. This is their second legal go-round, as the case was dismissed in 2012 from federal court. It now sits in New York State Supreme Court.

“There is no document saying that Stettiner was the owner,” Golub tells The Post. “Even Stettiner’s friends said he was a holder of the painting, not the owner. Palmer’s strategy is to attack the Nahmads — saying that the family is a monopoly, saying that Helly [who served five months in prison on gambling charges in 2014] is a criminal — to bring about a settlement.”

Helly Nahmad tells The Post, “[Mondex] is trying to use bad publicity to force my family into a settlement. All they seem to care about is money. They don’t care about the plaintiff. They don’t care about art. They . . . don’t do their research.”

In response to demands that he show definitive proof of the painting’s ownership, Palmer replies, “Do you know what Jewish people in France were doing during the war? They were running for their lives.”

‘It’s unethical to build an entire business model around [finding] things looted from Jews, just to get a percentage, and cloaking it in the pretext of seeking justice.’

- Marc Masurovsky of the Holocaust Art Restitution Project

Even if the art proves looted, Marc Masurovsky of the Holocaust Art Restitution Project expresses little regard for those, like Palmer, who pursue for-profit Nazi-related restitution.

“It’s unethical to build an entire business model around [finding] things looted from Jews, just to get a percentage, and cloaking it in the pretext of seeking justice,” he says.

The Canadian-born Palmer — who signs emails “Esq.” even though he “has an interest in law” but is not an attorney — insists: “We’re doing good by helping people to recover art that they would have a hard time recovering without our help.”

Palmer is tight-lipped about how much art or money he has recouped. Clients who do win often have to sell their freshly-found family heirloom in order to make good on Mondex’s bill (though they can also keep substantial profits). Palmer admits this will likely be the case if Maestracci prevails against the Nahmads. “What’s he going to do?” Palmer asks about the modestly living Frenchman. “Put a Modigliani in his house and wait for someone to . . . steal it?”

Says an expert in the nonprofit art world: “What Palmer does is not entirely wrong. The problem is how he does it. He uses Wild West techniques.”

Michel Strauss knows this well. The former head of the impressionist modernist department at Sotheby’s in London, Strauss was contacted by Palmer around 2014.

Edgar Degas’ “Dancers”

“He sent a letter saying that a Degas, which once belonged to my grandfather, may have been stolen [by Nazis]. He told me that they could research it and get me restitution,” Strauss tells The Post.

But Strauss did his own research and “proved to my satisfaction that the painting had been sold at my grandfather’s auction to a French singer, Simone Berriau, in 1932.”

Palmer’s reaction to the news? “He was a bit pissed off at me,” says Strauss. “He tried to insist and insist” that the painting had been stolen from Strauss’ grandfather.

“[Palmer is] trying to do business at any cost without knowing the full facts.”

Palmer responds, “When we approached Michel Strauss, it was on the basis of preliminary research. It’s easy at that point to arrive at incorrect conclusions.”

Still, he says, “I can’t think of a situation where we approached someone and were wrong.” Even regarding a case in Holland, where courts decided that his clients were not the heirs to a Salomon Koninck painting, “Old Man With Beard,” Palmer says, “We did not have sufficient information. But that doesn’t mean it wasn’t looted.”

Where the Nahmads are concerned, Strauss believes that Palmer has his work cut out for him.

“[Palmer is] not going to get a penny out of the Nahmads,” Strauss says. “They are professionals, they know the history of their pictures and they will not pay out anything to get rid of somebody.”